Devices incorporating Nitinol actuating elements, (specifically Flexinol 100 HT manufactured by Dynalloy of Irvine, Calif.), which contract when heated by an adequate electric current to provide a repeatable muscle effect producing motion such as periodic wing flapping in model insects or limb movement in other robotic creatures, have been known and used for many years. Various embodiments of SMA actuating elements (known as Muscle Wires, which is a registered trademark of Mondo-tronics Inc of San Rafael, Calif.), are described in the RobotStore catalogue, published 1998 by Mondo-tronics. Inc of San Rafael Calif.
However, for some potential applications, such as when power is supplied by a small photoelectric (solar) cell or with a set of rectified low current Christmas tree lighting decorations, (involving single bulb replacement by an SMA device), the level of current supplied continuously by the source is too low to heat the element sufficiently for effective operation by direct connection. In addition, conventional charge storage devices such as high capacity low resistance capacitors are rated for operation only in low voltage applications.